Move docs to mkdocs and improve them

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

docs/administration/upgrading.md

@@ -0,0 +1,91 @@
+---
+title: Upgrading to a new release
+---
+
+# Preparing
+
+The release page contains a changelog, and below it, upgrade instructions. **Read and understand** the release instructions.
+
+Some tasks (like database migrations) can take a while, so we advise you to run commands inside a `tmux` or `screen`.
+
+# Backup
+
+Always make sure your database and `.env.production` file are properly backuped before performing upgrades.
+
+Unless stated otherwise in the release notes, the following steps are enough to upgrade Mobilizon.
+
+# Steps
+
+### Fetch latest code
+Switch to the `mobilizon` user:
+
+```bash
+sudo -i -u mobilizon
+```
+
+And navigate to the Mobilizon root directory:
+
+```bash
+cd /home/mobilizon/live
+```
+
+Fetch the latest tags
+```bash
+git fetch --tags
+```
+
+And checkout the tag you want to switch to. For instance, if I want to upgrade to version `v1.1`:
+```bash
+git checkout v1.1
+```
+
+### Fetch new dependencies
+Fetch new and/or updated Elixir and NodeJS dependencies
+```bash
+mix deps.get
+```
+```bash
+cd js
+yarn install
+```
+
+### Rebuild Mobilizon's front-end
+```bash
+yarn run build
+cd ../
+```
+
+### Recompile Mobilizon
+```bash
+mix compile
+```
+Let's switch back to your regular user.
+
+### Stop running Mobilizon processes
+```bash
+sudo systemctl stop mobilizon
+```
+
+### Perform database migrations
+
+Go back to the `mobilizon` user.
+```bash
+sudo -i -u mobilizon
+cd live
+mix ecto.migrate
+```
+### Restart Mobilizon
+Let's switch back one last time to your regular user.
+```bash
+sudo systemctl restart mobilizon
+```
+
+You can follow the Mobilizon logs to check that everything works properly. 
+```bash
+sudo journalctl -u mobilizon -f
+```
+
+**That’s all!** You’re running the new version of Mobilizon now.
+
+If you have issues after upgrading, try reviewing upgrade steps and release notes.
+Then feel free to [contact us](../about.md#discuss) or file an issue on [our Gitlab](https://framagit.org/framasoft/mobilizon/issues)